<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script>
        function changeattyibute(){
            var in1=document.getElementById("in1")
            in1.type="button"
            in1.value="嗨"
        }
        function changeStyle(){
            var in1=document.getElementById("in1")
            in1.style.color="green"
            in1.style.borderRadius="10px"
        }
        function changeText(){
         var div=document.getElementById("hello")
         div.innerText="嗨"
         div.innerHTML="<h1>嗨</h1>"
        }


    </script>
    <style>
        #in1{
            color: red;
            border-radius: 5px;
        }
    </style>
</head>
<body>
    <input id="in1" type="text" value="hello">
    <hr>
    <div id="hello">
        hello
    </div>


    <hr>
    <button onclick="changeattyibute()">变</button>
    <button onclick="changeStyle()">操作样式</button>
    <button onclick="changeText()">操作文本</button>
</body>
</html>